Dual-cylinder vehicle lift

ABSTRACT

A vehicle lift primarily intended for lifting loaded trucks and trailers at the axle, the lift having a portable base, there being a pair of shiftable cylinders on the base and means for shifting the cylinders between a lowered position and raised positions, such means including a compressed air plumbing system for the lift whereby air may be delivered into a tubular handle which is pivotally mounted with respect to the common top plate of the cylinders and thence into a space defined by said top and a fixed piston and packing seal corresponding to each cylinder whereby the cylinders are raised; there being a centrally disposed lift post coupled with the cylinders and adjustable vertically with respect thereto whereby the effective height of the lift may be selectively adjusted.

llnite States Patent Primary Examiner- Lester M. Swingle AssistantExaminer-David R. Melton Attorney-Schmidt, Johnson, Hovey & WilliamsABSTRACT: A vehicle lift primarily intended for lifting loaded trucksand trailers at the axle, the lift having a portable base, there being apair of shiftable cylinders on the base and means for shifting thecylinders between a lowered position and raised positions, such meansincluding a compressed air plumbing system for the lift whereby air maybe delivered into a tubular handle which is pivotally mounted withrespect to the common top plate of the cylinders and thence into a spacedefined by said top and a fixed piston and packing seal corresponding toeach cylinder whereby the cylinders are raised; there being a centrallydisposed lift post coupled with the cylinders and adjustable verticallywith respect thereto whereby the effective height of the lift may beselectively ad justed,

PATENTH] SEP 2 8197i AoRNEm DUAL-CYLINDER VEHICLE LllF'll It is the mostimportant object of this invention to provide a heavy-duty vehicle liftwhich is portable but yet which may be utilized to lift loaded trucks,trailers and the like at the axle, the lift having a base and a pair ofshiftable cylinders on the base, the cylinders being interconnected by apair of spaced, vertical plates which cooperate with the cylinders todefine a well, there being a lift post received within the well andselectively vertically adjustable therein whereby the overall height ofthe lift may be determined, depending upon the particular use to whichit is to be put.

It is yet another object of this invention to provide a common top forthe pair of cylinders, the top having a handle pivotally connectedthereto, the handle being L-shaped and presenting a minor leg and amajor, longer leg, the handle being swingable with respect to the topwhereby the major leg may be positioned in overlying relationship to thetop for purposes of storage.

Yet another aim of this invention is to provide, in a vehicle lift, aplumbing system for delivering compressed air from an outside source tothe cylinders of the lift, the plumbing system being integrated into thelift in such a way that no unsightly pipes, hose or the like areexposed, the plumbing system including a tubular handle to which air isdelivered through a valve from an outside source, a pivotal connectionbetween the handle and the top of the lift, said pivotal connectionbeing suitably provided with passageways whereby air may movetherethrough and along beneath the top of the lift and into each of thecylinders whereby to enter a space defined between the lower surface ofthe top and a piston and packing seal which are fixedly held withrespect to the base, all to the end that the cylinders may besimultaneously shifted from a lowered position to raised positions asdetermined by the operator of the lift.

Other objects of this invention include details of construction; themanner in which the components of the lift are assembled relative to oneanother, whereby metal-to-metal contact between such components isavoided; and the assembly of the lift in such a manner that it maytolerate a considerable amount of angular misalignment, all of whichwill become apparent from the following specification.

ln the drawing:

FIG. 1 is a top plan view of a vehicle lift, portions beingfragmentarily illustrated and shown in cross section for clarity ofdisclosure;

FIG. 2 is a sectional view taken along line 22 of FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is a fragmentary, elevational view of the connection between thehandle and the lift; and

FIG. 5 is a sectional view taken along line 55 of FIG. 4.

The vehicle lift, broadly designated by the numeral 10, includes as itsprimary components, a base 12 which is in the nature of a flat plate,the base having a pair of cylinders 14 and 16 disposed thereon inlongitudinally aligned relationship, the cylinders 14 and 16 beingshiftable with respect to the base 12 and primarily defining theshiftable portion of lift 10. Cylinder 14 carries a normally forwardlyextending bracket 18 which receives axle 20 whereby to mount a pair ofmetal wheels 22 on said cylinder 14, said front wheels being utilizedprimarily in positioning the lift with respect to the load to be lifted.

Cylinder 16 carries a pair of spaced, normally rearwardly projectingextensions 24 which receive in transverse relationship thereto an axle26 whereby to rotatably carry spaced,

semipneumatic wheels 28, which wheels are of larger diameter than wheels22 and are primarily utilized in moving the lift 10 from one position toanother. Wheels 28 also cooperate with wheels 22 as an aid inpositioning the lift 10 with respect to the particular load to belifted.

The bracket 18 is secured to the outer surface 30 of the cylinder 14,and the extensions 24 are secured to the outer surface 32 of thecylinder 16. Each of the cylinders is annular in configuration and isindependently encased by its circum scribing wall, the wall 34 ofcylinder 14 having outer surface 30 and an inner surface 36, and thewall 38 of cylinder 16 having outer surface 32 and an inner surface 40.

The adjacent outer surfaces 30 and 32 of the cylinders 14 and R6 arejoined by a pair of spaced-apart, vertically disposed plates 42 at aposition centrally of the base 12, the plates 42 cooperating with theouter surfaces 30 and 32 of the cylinders 14 and 16 to define acentrally positioned well 44. The well 44 receives a lift post 46therewithin in a manner clearly shown in FIGS. 2 and 3 of the drawing,the lift post extending through the top 48 of the lift, which top 48 iscommon to both cylintiers and has an opening 50 formed therein in acentral position whereby to permit the lift post 46 to be positionedwithin the well 44.

The lift post 46 is provided at its upper end with a lift pad 52 and thewalls of the lift post which are next adjacent the vertical plates 42are provided with a series of apertures 54 which are selectivelyalignable with opposed, aligned holes 56 which are formed in thevertical plates 42. As is evident, the foregoing construction permitsthe lift post 46 to be selectively and vertically adjusted within thewell 44 therefor, permitting the desired positioning of lift pad 52 withrespect to the top 48 of the lift 10, all to the end that severaldifferent overall heights of the lift may be provided, depending uponthe load to be lifted and the position thereof. Thus, the lift post 46might be adjusted to its lower position if the lift were to be used forraising a truck tractor by the front axle thereof, but yet might bemoved to one of its raised positions if the lift is to be used inraising a trailer for instance, by its nondriving rear axle. In order tolock lift post 46 with respect to well 44, a cross pin 58 is provided asshown in FIG. 3 whereby post 46 may be lifted to the selected positionand apertures 54 aligned with holes 56, pin 58 then being insertedthrough the aligned holes and apertures to cause post 46 to be movedfrom a lowered position to raised positions as the cylinders 14 and 16are shifted from a lowered position to raised positions. A pair ofopposed stops 60 are carried by the outer surfaces 30 and 32 of cylinderwalls 34 and 38 for engagement with a lift post stop bar 62 whereby toprevent removal of the lift post 46 from its well 44 and to also preventunsafe positioning of the lift post. It will be appreciated that pin 58may be inserted through vertical plates 42 and lift post 46 from eitherside of the lift inasmuch as it is readily accessible from both sidesthereof, this facilitating positioning of the lift post 46 and couplingthereof with the plates 42 and thus with cylinders 14 and 16.

The cylinders 14 and 16 are each identical in internal construction,only one being described hereinafter. Thus, cylinder 14, for example isdefined by annular sidewall 34, there being a centrally disposed sleeve64 disposed within the confines of wall 34, said sleeve serving tosupport a piston 66 which is essentially the same diameter as theinternal diameter of cylinder 14 the piston 66, in turn, supporting acup-shaped packing seal 68 which fully overlies the normally upper faceof the piston 66 to provide a seal between the piston and the innersurface 36 of the cylinder 14.

Sleeve 64, piston 66 and cup seal 68 are fixed with respect to the base12, this being accomplished by the provision of a stationary center bolt70 which extends between a threaded boss 72 provided on the normallylower surface of the piston 66 and the base 12, there being a head 74for drawing said bolt 70 tight whereby to secure the sleeve 64, piston66 and cup seal 68 with respect to cylinder 14. A plug 71 is welded topiston 66, extends through the piston and beyond the packing seal, andis provided with a retaining ring and washer assembly 76 in overlyingrelationship to the cup seal 68 whereby to retain the same.

The circumferential edge of piston 66 is provided with a bearing ring 78which is preferably formed from a suitable plastic material, the ring 78bearing against the inner surface 36 of the cylinder 14 whereby toprevent metal-to-metal engagement between said surface 36 and thecircumferential edge of the piston 66. To further avoid metal-to-metalcontact, the cylinder 14 carries an annular cylinder guide 80 on theinner surface 36 thereof, the cylinder guide being provided at it innermost circumferential edge with an annular bearing 82, which is incontinuous engagement with the outer face of the center sleeve 64.

The packing cup seal 68 is preferably formed from an oil andgreaselresistant rubber material and the bearing ring 78 and bearing 82are formed from a suitable bearing material, the ring 78 and bearing 82extending sufficiently beyond the surfaces by which they are carried topreclude metal-to-metal contact between any of the components of thecylinder as the cylinder is shifted between its various positions.Furthermore, the provision of the bearing 82 and bearing ring 78 resultin the cylinder 14 being able to tolerate a considerable amount ofangular misalignment inasmuch as even if such misalignment occurs, thering 78 and annular bearing 82 will compensate therefor while stillpreventing metal contact, there being adequate radial clearance betweenthe metal parts of each of the cylinders. Likewise, the cup-type pistonseal 68 will accommodate a substantial amount of angular misalignmentand still maintain its sealing relationship, thereby permittingcontinuing functioning of the lift and with little or no relubricationrequired during normal use thereof.

The lift is provided with a handle 84 which is generally L- shaped inconfiguration whereby to present a minor leg 86 and a major, longer leg88, the handle 84 being tubular in cross section whereby air may passtherethrough in a manner for purposes hereinafter described. The handle84 is provided with gripping members 90 at the free end thereof, saidgripping members having a three-way manually controlled spring returnair valve 92 disposed therebetween, which valve is covered by a valvecover plate 94 spanning the distance between said gripping members 90,there being an operating lever 96 for said valve 92 carried between saidgripping members 90 and in easy reach of the operator of the lift.

The minor leg 86 of handle 84 is pivotally connected to the lift 10 byvirtue of a pivot pin 98, which pin connects said leg 86 to a pair ofspaced-apart pieces 100 and 102, piece 100 being a rearwardly extendingbracket which is secured to the lower surface of the top 48 of the lift,and piece 102 being in the nature of a sector plate which is likewisesecured to the lower surface of the top 48, the sector plate beingprovided with a plurality of radially spaced slots 104, which slotsselectively receive a detent 106 which is spring loaded as by torsioncoil spring 108 and coupled with a suitable operating rod 110 which iscontrolled by a lever 112 which forms an extension of the rod 110 and ispositioned adjacent the handle-gripping members 90 of the lift 10.

It will be appreciated from the foregoing that, by operation of rod 110,the handle 84 may be swung to any position about its pivot pin 98 andtherefore virtually any position with respect to the lift 10, it beingcontemplated in the embodiment chosen for illustration that fouroperating positions will be available, these being represented by thefour slots 104 in the sector plate 102, the detent-l06 serving to lockthe handle in any one of the four selected operating positions. When thelift 10 is to be stored, the rod 110 may be actuated whereby to removedetent 106 from any of the slots 104 and handle 84 then may be swung ina generally forward direction about pivot 98 whereby major leg 88 of thehandle 84 is in overlying relationship to the top 48 of the lift 10.

The lift 10 is provided with a plumbing system for delivering air froman outside source of compressed air to a point whereby to result inraising of the cylinders 14 and 16. The plumbing system commences withan inlet elbow 114 which is adapted to suitably coupled with a hose bywhich compressed air can be delivered into the valve 92, the air thenpassing through said valve 92, when the same is opened throughutilization of lever 96, and along the tubular major leg 88 and intotubular minor leg 86. The air then passes from minor let 86 into atransverse passage 116 formed in rotatable pin 98, and thence along alongitudinal passage 118, through a rotary seal 120 and into a passage122 drilled in sector plate 102, the air passing from passage 122through a further passage 124 formed over the wall 38 of cylinder 16whereby to enter a space 126 which is defined between the cup seal 68 ofcylinder Once compressed air has reached space 126 it passes outwardlytherefrom through a notch in top plate 48 and into passage 132 which isdefined by a channel 134 secured to the undersurface of top 48 betweenthe cylinders 14 and 16, and passage 132 delivering the air through anotch formed in the undersurface of top 48 and thence into a space 138defined between the piston 66 and cup seal 68 of cylinder 14 and thatportion 140 of the top 48 which overlies said piston and cylinder.

Thus there is provided a plumbing system for delivering air into thelift, which plumbing system is inconspicuous in that it is entirelyinternal of the lift, utilizing the tubular handle 84, the means forpivotally connecting the handle 84 to the top 48 and the air passage 132which is formed beneath the top 48 of the lift.

It is to be noted that the components of the lift 10 are of such anature that assembly thereof is facilitated during the manufacturingoperation inasmuch as the lift may be inverted from its normal positionwhereby to commence assembly with the top 48 being lowermost, thecylinders then being positioned thereon in the desired relationship andthose components which are received within the cylinder then beingpositioned by placing them within the cylinders 14 and 16, this beingeasily accomplished inasmuch as the hole in the base which receives thecenter bolt 70 is oversize as is the hole in the piston whichaccommodates the bolt 70, such construction permitting one man to easilyassemble the lift 10 and all of the various components thereof andminimizing the effect of misalignment between the base and theassemblies carried thereby.

Operation of the lift is achieved by initially positioning the lift post46 in its desired position whereby to create the necessary overallheight for the lift according to the particular purpose for which is isto be used. Actuation of control lever 96 permits air to enter throughvalve 92 and through the plumbing system hereinabove described intospaces 126 and 138. The air thus admitted shifts the cylinders in anupward direction inasmuch as a force is exerted on those portions 128and 140 of top 48 which are in overlying engagement to the pistons 66 ofthe corresponding cylinders, such upward shifting serving to move liftpost 46 into engagement with the vehicle to be lifted and thencesubsequently raise the vehicle. Thus, lift is applied to the vehiclethrough the centrally located post 46 and, more particularly, pad 50thereof which is in actual contact with the vehicle to be lifted. Whencylinders l4 and 16 are raised as described, the wheels 22 and 28 arelifted out of engagement with the lift supporting surface, such as afloor or the ground, whereby to cause base 12 to be dropped intoengagement with such surface and thus support the lift 10 as thecylinders 14 and 16 are moved to their raised positions.

The lift is lowered by reverse operation of the control valve 92 bylever 96 which allows the air in the cylinders to exhaust to theplumbing system referred to above. In order to insure full return of thecylinders 14 and 16 to their lowered positions, there are provided apair of coil return springs 142, said return springs having one endthereof coupled with a lug 144 on the base 12 and the other ends eachcoupled with a corresponding lug 146 on the top 48. The return springsare particularly used to return the cylinders and top to a loweredposition when the lift post 46 is not loaded and said return springs 142also serve to prevent separation of the top 48 and the base 12 when thelift 10 is being moved from place to place.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

l. A vehicle lift comprising:

a portable base;

a pair of shiftable cylinders on said base;

' means for shifting said cylinders between a lowered position andraised positions;

a pair of spaced plates interconnecting said cylinders, said platescooperating with said cylinders to define a well therebetween;

a lift post received within said well and selectively verticallyadjustable therein; and

means coupling said post with the plates whereby said post is moved froma lowered position to raised positions as said cylinders are shifted.

2. A vehicle lift as set forth in claim 1, there being a common top forsaid cylinders, said top having an opening formed therein for said well,said top being shiftable with said cylinders.

3. A vehicle lift comprising:

a portable base;

a pair of shiftable cylinders on said base;

means for shifting said cylinders between a lowered position and raisedpositions; and

a handle connected to the shiftable portion of said lift, said handlebeing tubular and having a minor leg and a major, longer leg, saidhandle being swingable with respect to said cylinders to a position withsaid major leg overlying said cylinders.

4. A vehicle lift comprising:

a portable base;

a pair of shiftable cylinders on said base;

means for shifting said cylinders between a lowered position and raisedpositions; and

a handle connected to the shiftable portion of said lift, said means forshifting said cylinder including a compressed air plumbing system, saidsystem including the handle and passage means for delivering air fromthe handle into the cylinders.

5. A vehicle lift as set forth in claim 4, there being an air inletvalve on one end of the handle and in communication with the handle fordelivering compressed air into said plumbing system.

6. A vehicle lift comprising:

a portable base;

a pair of shiftable cylinders on said base, there being a piston withineach of said cylinders and a packing seal in normally overlyingrelationship to each of said pistons,

there being an air-receiving space between each of said seals and thetop of the corresponding cylinder;

means for shifting said cylinders between a lowered position and raisedpositions;

a handle connected to the shiftable portion of said lift; and

a compressed air plumbing system in communication with said spaces, saidplumbing system being defined in part by said shiftable portion of thelift.

7. a vehicle lift as set forth in claim 6, said pistons and said sealsbeing fixed to said base.

8. A vehicle lift as set forth in claim 6, there being a bearingcircumscribing each of said pistons and in engagement with the innerfaces of corresponding cylinders as the same are shifted with respect tothe pistons as a result of introduction of air into said spaces.

9. A vehicle lift as set forth in claim 6, there being at least onereturn spring interconnecting the fixed base and the shiftable portionwhereby to return said cylinders from a raised to a lowered positionwhen air is evacuated from said spaces.

110. A vehicle lift comprising:

a portable base;

a pair of shiftable cylinders on said base;

means for shifting said cylinders between a lowered position and raisedpositions;

a handle for said lift; and

a pair of wheels carried by each of said cylinder, the pair of wheelsproximal to said handle being of larger diameter than the other pair ofwheels.

11. A vehicle lift comprising;

a portable base;

a pair of shiftable cylinders on said base;

means for shifting said cylinders between a lowered position and raisedpositions;

a handle for said lift, said handle being pivotally connected to theshiftable portion of the lift and swingable to selected positions withrespect to said lift; and a pair of wheels carried by each of saidcylinders.

1. A vehicle lift comprising: a portable base; a pair of shiftablecylinders on said base; means for shifting said cylinders between alowered position and raised positions; a pair of spaced platesinterconnecting said cylinders, said plates cooperating with saidcylinders to define a well therebetween; a lift post received withinsaid well and selectively vertically adjustable therein; and meanscoupling said post with the plates whereby said post is moved from alowered position to raised positions as said cylinders are shifted.
 2. Avehicle lift as set forth in claim 1, there being a common top for saidcylinders, said top having an opening formed therein for said well, saidtop being shiftable with said cylinders.
 3. A vehicle lift comprising: aportable base; a pair of shiftable cylinders on said base; means forshifting said cylinders between a lowered position and raised positions;and a handle connected to the shiftable portion of said lift, saidhandle being tubular and having a minor leg and a major, longer leg,said handle being swingable with respect to said cylinders to a positionwith said major leg overlying said cylinders.
 4. A vehicle liftcomprising: a portable base; a pair of shiftable cylinders on said base;means for shifting said cylinders between a lowered position and raisedpositions; and a handle connected to the shiftable portion of said lift,said means for shifting said cylinders including a compressed airplumbing system, said system including the handle and passage means fordelivering air from the handle into the cylinders.
 5. A vehicle lift asset forth in claim 4, there being an air inlet valve on one end of thehandle and in communication with the handle for delivering compressedair into said plumbing system.
 6. A vehicle lift comprising: a portablebase; a pair of shiftable cylinders on said base, there being a pistonwithin each of said cylinders and a packing seal in normally overlyingrelationship to each of said pistons, there being an air-receiving spacebetween each of said seals and the top of the corresponding cylinder;means for shifting said cylinders between a lowered position and raisedpositions; a handle connected to the shiftable portion of said lift; anda compressed air plumbing system in communication with said spaces, saidplumbing system being defined in part by said shiftable portion of thelift.
 7. a vehicle lift as set forth in claim 6, said pistons and saidseals being fixed to said base.
 8. A vehicle lift as set forth in claim6, there being a bearing circumscribing each of said pistons and inengagement with the inner faces of corresponding cylinders as the sameare shifted with respect to the pistons as a result of introduction ofair into said spaces.
 9. A vehicle lift as set forth in claim 6, therebeing at least one return spring interconnecting the fixed base and theshiftable portion whereby to return said cylinders from a raised to alowered position when air is evacuated from said spaces.
 10. A vehiclelift comprising: a portable base; a pair of shiftable cylinders on saidbase; means for shifting said cylinders between a lowered position andraised positions; a handle for said lift; and a pair of wheels carriedby each of said cylinders, the pair of wheels proximal to said handlebeing of larger diameter than the other pair of wheels.
 11. A vehiclelift comprising; a portable base; a pair of shiftable cylinders on saidbase; means for shifting said cylinders between a lowered position andraised positions; a handle for said lift, said handle being pivotallyconnected to the shiftable portion of the lift and swingable to selectedpositions with respect to said lift; and a pair of wheels carried byeach of said cylinders.